Speed control for gas turbine engines

ABSTRACT

A governor mechanism for controlling the speed of a gas turbine engine comprising a spring means arranged to control the resistance to movement of governor elements, a plurality of pistons independently actuable to control the spring force through lever mechanisms, the pistons being connected by cams and followers, whereby they can be operated independently or in combination.

United States Patent Inventor Joseph Lewis Bloom Baie D'Urfe, Quebec, Canada 779,346

Nov. 27, 1968 Sept. 7, 1971 Joseph Lucas (Industries) Limited Birmingham, England App]. No. Filed Patented Assignee SPEED CONTROL FOR GAS TURBINE ENGINES 4 Claims, 1 Drawing Fig.

US. Cl 73/541 Int. Cl G01p 3/16 Field of Search 73/540,

[56] References Cited UNITED STATES PATENTS 3,111,809 11/1963 Bierwirth 60/3928 3,348,375 10/1967 Gardner et a1 60/3928 3,382,673 5/1968 Mowbray 73/543 X FOREIGN PATENTS 175,724 2/1922 Great Britain 73/543 Primary Examirier-lames J. Gill Attorney-Holman & Stern ABSTRACT: A governor mechanism for controlling the speed of a gas turbine engine comprising a spring means arranged to control the resistance to movement of governor elements, a plurality of pistons independently actuable to control the spring force through lever mechanisms, the pistons being connected by cams and followers, whereby they can be operated independently or in combination.

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mmh l PATENTED SEP 7197: 3.6031 60 ATTORNEYS b..,when increased water/methanol injection is required to increase mass flowthrough. the engine and hence thrust,

from the engines, the possible maximum speed which the engine. can reach has to be increased in order to maintain jet pipe temperature,

c. when air is being supplied from theengine to control surfaces on the aircraft, .this usually being referred to as boundary layer control, possible maximum speed which the engine can reach has to be. decreased.

An object of the present invention is to .provide a con-.

venient governor mechanism for controlling the speed of a gas turbine engine under-certain conditions, independently or in. conjunction with one another.

According to the presentinventiontthere is provided a governor mechanism for controlling the speed of a gas turbine engine comprising spring means arrangedto provide antadjustable resistance to movement of centrifugally operable governor elements, to control fuel flow to the engine, a lever mechanism operable to control the spring force resistance, and a plurality of independently actuable pistons arranged to control :the spring force resistance and hence enginespeed,

through the intermediary of the lever mechanism, each of said pistons being interconnected by'a system of cams and cam fol-' lowers whereby any one of .said'pistonscan be operated independently of the others, or in combination.

An embodiment of the invention will now be described, by wayof example, with reference to the accompanying drawing which is a diagrammatic representation of top speed governor mechanism for controlling the speed of :a .gas turbine engine for an aircraft. 1

Referring. to the drawing,'tl1e mechanism shown is part of a fuel control system for a gas turbine engine, which includes a i set of governor weights whereby fuel flow to the engine is controlled. A spring 1 actson an axially slidable spring-loaded.

plunger A to provide a resistance to movement of the governor weights whichare of the centrifugal type, in such manner as to limit the maximum speed which the engine can reach. The spring 1 acts between the closed end of anenclosing cup la of at Ibto a lug on the end of the fixed cylinder in which the piston A slides. The cylinder is fixed relatively to a body 26 of the apparatus. The opposite end of the spring 1 .acts against a flange 20 on a spindle 2. The spindle 2 is pivotally connected at 2bonto. the plunger A, at which point, lever 3 isalso pivotallyconnected. The free end 2c of the spindle 2 remote from the pivot 2b is slidably engaged in a long bearing sleeve formed integrally in the interior of the cup In The other end i of the lever 3 is pivotally connected to a a lever 4 and a roller 5- is provided at .this junction. The lower end of they lever4is pivotally connected to a lever ,6 which carries a roller 7 intermediate its ends and which engages a cam 87 connected through a link 80 to a pilot-operated lever. The other end of s the lever 6 is connected. through further levers 9; 10 to a rod 11 which is connected with a part movable in accordance with changing temperature. in the jet pipe of the engine. In use,

axial movement of the rod 11 takes place inaccordance with Abutting against the roller 5 is a cam 13 pivoted at its lower end to one arm of a bellcrank lever l4. -The bellcrank lever .14

acts about a pivot 15 and its other arm carries a roller 16 which engages a cam surface on a cam 17 pivotally mounted at-the end of a hydraulicallyoperated piston 18 associated with a water/methanol injection system (not shown) of the engine. Extending parallel to the piston 18 are two further pistons 19, 20, the piston 19 being'associated with the boundary layer control mechanism and carrying aroller 21- through the intermediary of arm 22 which is pivotally attached to piston 19. The roller 21 is slidable axially of the piston between the cam 17 and a cam surface on a cam 23 pivotally carried by the piston 20 which is operable in order to increase power for short distance takeoff or landing of the aircraft. The cam 23 is slidable between the roller 21 and a fixed roller 24.

The three pistons 18, 19 and 20are each controllable by the aircraft pilot.

The bell crank lever 14 is provided with a screw adjustment 25 which positions the cam 13 to permit variation of he rating of the governor spring 1.

With the above arrangement, increase in power for short takeoff or landing can be effected by actuation of piston 20; decrease-in engine speed for boundary layer control can be effected by actuation of piston-19; and increase in; engine speed to accommodate water/methanol injection can be effected by Piston l8. I

For example, if the piston ,20. is to be operated independently of pistons 18 and 19," the cam 23 is moved to the left as shown in the drawing. Due to action of the cam surface on the cam 23 against ,the roller 21, the latteris urged downwardly together with the cam 17. and the roller16 to pivot the bellcrank lever.l4'about itspivotJS. ln'doing so the associated cam 13* urges the roller 5 to .the left. Suchnrdvement of the rollerS causes the plunger A to move as drawn. Because the spindle 2 is pivotally connected to theplunger and because the cup la is on a fixed pivot lb. not connected to the plunger A, the spring 1 and the cup lb. will pivot in an anticlockwisedirectiom Thiswill relax the spring tochange the force which it exerts to resist the tendency of the centrifugal governor weights to operate to increase fuel supply and thus to increase engine speed.

If on the other hand decrease in engine speed is desired in relation to boundary layer control, the reverse procedure takes place on operation of piston 19 The piston 19 is moved to the left asshown in the drawingand this perrnitsthebellcrank lever .14 to pivot in an anticlockwise dire c on hich in turn allows the roller 5 to move to the right and so pivot the spring 1 and its associatedspindle 2 and cup la in a clockwise directionand to move the plunger downwards to decrease the resistance. against the centrifugal governor weights and so decrease engine speed.

Actuation of piston 18 effects a control 'similarto thateffected by piston 20., I

In addition to independent control of the three pistons l8, l9 and 20,-it will be apparent that any two or all three can be operated simultaneously and in this case an engine maximum speed setting is obtained which is determined by the compound motion of a plurality of the pistons. i

Having thus described my invention what I claim as new and desire to secure by letters .Pat. is:

l. A governor mechanism for controlling the speed of a gas turbine engine comprising aspeed-responsive device, means forcontrollingthe supply of fuel to the engine in accordance with said speed-responsive device, a plunger slidably mounted in a fixed body, means connecting the plunger with the speedresponsive device, spring means acting on the plunger, ,the spring means actingiat one end through a pivot, on the plunger and, at its other end through a further pivot, on a fixed part of the body, a lever. mechanism pivotally connectedto the plunger at the end thereof at which the spring means acts, movement of said lever mechanism moving the plunger which causes the spring means to be moved angularlyto adjust the force which it applies to the plunger, to control the speedresponsive device, a plurality of 'cams acting upon the lever mechanism. and a plurality of independently operable pistons ried on a pivoted bell crank lever whichis positioned by the plurality of cams associated with the pistons respectively.

3. A governor mechanism as claimed in claim 1 which the lever mechanism has a manually operable means whereby it can be adjusted independently of the pistons.

4. A governor mechanism as claimed in claim 1 in which the lever mechanism has a further associated control whereby it can be adjusted independently of said pistons. 

1. A governor mechanism for controlling the speed of a gas turbine engine comprising a speed-responsive device, means for controlling the supply of fuel to the engine in accordance with said speed-responsive device, a plunger slidably mounted in a fixed body, means connecting the plunger with the speedresponsive device, spring means acting on the plunger, the spring means acting at one end through a pivot, on the plunger and, at its other end through a further pivot, on a fixed part of the body, a lever mechanism pivotally connected to the plunger at the end thereof at which the spring means acts, movement of said lever mechanism moving the plunger which causes the spring means to be moved angularly to adjust the force which it applies to the plunger, to control the speed-responsive device, a plurality of cams acting upon the lever mechanism and a plurality of independently operable pistons connected to the cams respectively to control their positions, to control the position of the lever mechanism.
 2. A governor mechanism as claimed in claim 1 which the lever mechanism comprises a first lever pivotally connected at one end to the plunger, a roller carried at the other end of said first lever, a cam on which the roller acts, the cam being carried on a pivoted bell crank lever which is positioned by the plurality of cams associated with the pistons respectively.
 3. A governor mechanism as claimed in claim 1 which the lever mechanism has a manually operable means whereby it can be adjusted independently of the pistons.
 4. A governor mechanism as claimed in claim 1 in which the lever mechanism has a further associated control whereby it can be adjusted independently of said pistons. 